Depending on the processed material from each drill must be properly sharpened. To verify the correct angle will help a specially prepared square plate of copper or aluminium with a thickness of 1 mm.
To become operational protractor enough to cut it cut, as shown in the picture: a large cutout at an angle of 120 degrees, the other half is 60 degrees and the surviving corner of a square is 90.
Recommend to read
SMALL SPOOL…
Large problems sometimes arise because of the small details. Take, for example, the servo-mechanism, reduces the efforts on arms control such a powerful and popular tractors as...
FROM THE SYRINGE INTO THE WALL
Even a disposable syringe can still be of use, and more than once — of course, for other purposes. For example, the packing case of needle incised along the axis, it is suitable for use...
